In a conventional flip-chip package, a IC chip with a plurality of bumps is directly flip-chip mounted on a substrate, such as a printed circuit board or ceramic circuit board. A conventional flip-chip package had been brought up from R.O.C. (Republic Of China, Taiwan) Patent No. 457664 entitled “directly-downset flip-chip semiconductor package and its manufacturing process”. A chip is flip-chip mounted onto a substrate with a chip-cavity. The chip cavity of the substrate forms a plurality of dimple bonding pads for bonding the bumps of the chip. Due to the different thermal expansion coefficient between the chip and the substrate, the flip-chip mounting region (i.e. bumps) of the chip bears considerable thermal stress so that a warpage or bump-breaking easily takes place on the substrate.
In order to solve the problem of warpage on the substrate caused by thermal stress, a flip chip package had been disclosed in R.O.C. Patent No. 489,496 that a filling compound with a larger coefficient of thermal expansion (CTE) than that of the substrate is coated around the flip-chip region of the substrate for lessening substrate warpage of flip-chip package. But the chip is still directly flip-chip mounted on the substrate, such as ceramic or printed circuit board. The stress still exists at the chip. Flip-chip pads formed on the substrate are critical to match the fine pitch bumps of flip chip, and also the entire flip chip package has a thicker thickness.